The invention described herein relates generally to opto-electric connectors.
Due to increasing need for bandwidth, modem computer and communication networks are placing increasing reliance on optical signal transmission through fiber optic cabling. Fiber optic cabling is very efficient for transferring data as light signals. Unfortunately, there is still no efficient way to xe2x80x9cstorexe2x80x9d or xe2x80x9cprocessxe2x80x9d light signals representative of data. Thus, current technologies still require the conversion of optical signals into electronic signals prior to processing by various electronic devices and components. Therefore, networks will likely continue using fiber optics for transmitting data between nodes and silicon chips to process the data within the nodes for the foreseeable future.
Fiber optic transceivers, which convert light signals from a fiber optic cable into electrical signals, and vice versa, are used as the interface between a fiber optic line and a computer node. A typical transceiver includes one or more opto-electric semiconductor devices. Such opto-electric semiconductor devices can include optical receivers (optical detectors for converting light signals received over the fiber optic cables into electrical signals) and/or optical emitters (e.g. lasers) for converting electrical signals from the semiconductor devices into light signals. A number of fiber optic transceivers are commercially available from a variety of sources including Hewlett Packard, AMP, Sunitomo, Nortel, and Siemens.
In one known implementation, one or more optical transceivers are mounted directly onto a microprocessor or other electronic chip package. Optical fibers are optically connected and aligned with the transceivers using a connector apparatus. Such connections can be effective in transferring and converting optical signals into electronic signals (and vice versa). FIGS. 1 and 2 are simplified illustrations of one such approach. FIG. 1 shows a connector sleeve 10 having a chip-sub-assembly (CSA) 11 mounted thereon. Additionally, the chip-sub-assembly (CSA) 11 is mounted to a circuit board (not shown). An optical block 12 is mounted on top of the CSA 11. Photonic devices 13 are formed on the optical block 12. The photonic devices 13 are electrically connected to the CSA 11 using electrical connections formed on the optical block 12. Also, an optical fiber 17 is held by a ferrule 16. To connect the fiber 17 with the photonic device 13 (and thereby the CSA 11) the ferrule 16 is inserted (indicated by the arrow) into the sleeve 10. Referring to FIG. 2, the ferrule 16 is shown fully engaged with the sleeve 10 (contacting spacer 14) thereby aligning the fiber 17 with the photonic device 13. Thus, the interconnection of ferrule 16 with the sleeve optically aligns the fibers 17 with corresponding photonic devices 13. Typical examples of such devices are described in the above-referenced U.S. Patent Applications and U.S. Provisional Patent Applications.
One of the shortcomings of such implementations is that many of the connector components must be manufactured to relatively high tolerances in order to achieve the required optical alignment when the components are connected. Because the fiber is in one component and the photonic device is in another component, and due to the relatively precise nature of the optical connection between the fiber and photonic device, each time the connector components are connected there can be some uncertainty in the optical alignment. This has the effect of reducing the overall reliability of the connection. When subject to mechanical and environmental stresses during use, the connection can become misaligned.
Reflow temperatures can pose certain problems during the fabrication of optical components. To improve optical performance, lenses are commonly mounted on the photonic devices during manufacture. Such lenses are commonly constructed of plastics or other related materials. Such materials can become deformed at relatively low temperatures. During reflow processes (such as lead reflow processes used in leadless lead frame connection processes), lenses and other optical components can become damaged. This will become more of a problem as the industry moves away from lead processes (for environmental and other reasons, there is an increasing use of so-called xe2x80x9clead-lessxe2x80x9d processing) to other materials such as copper, tin, or other materials that require even higher process temperatures. Thus, developing a structure where the photonic devices and lenses are not subjected to these high temperatures is attractive.
Embodiments of the present invention include a variety of arrangements for electrically connecting a chip sub-assembly to electrical connections of photonic devices arranged on a separate optical sub-assembly.
In one aspect of the invention, a connector sleeve is provided that is suitable for receiving a connector plug, the connector plug having mounted thereon an optical fiber optically coupled to a photonic device with electrical connectors. The connector sleeve carries a chip sub-assembly with electrical connections for electrically connecting the chip sub-assembly to the optical sub-assembly when the connector plug is engaged with the connector sleeve.
In another aspect of the invention, a connector plug is provided that is suitable for engagement with a connector sleeve containing a chip sub-assembly. The connector plug includes an optical sub-assembly having photonic devices optically coupled to corresponding optical fibers and electrical connectors connected to the photonic devices. The electrical connectors are arranged such that an electrical connection is made between the photonic devices and the chip sub-assembly when the connector plug is engaged with the connector sleeve.
Another embodiment of the invention comprises a connector apparatus for electrically interconnecting a chip sub-assembly to an optical sub-assembly. The apparatus includes a connector sleeve and a connector plug. The connector sleeve is suitable for receiving the connector plug and has a chip sub-assembly with at least one electrical connection arranged thereon. The connector plug is suitable for engagement with the connector sleeve and contains an optical fiber, an optical sub-assembly including a photonic device that is optically coupled to the optical fiber, and electrical connectors corresponding to each photonic device. The connector plug is engaged with the connector sleeve, thereby electrically interconnecting the electrical connections of the chip sub-assembly to the electrical connectors of the optical sub-assembly such that electrical signals can pass between the chip sub-assembly and a photonic device of the optical sub-assembly.
Aspects of the invention also include a method for electrically interconnecting a chip sub-assembly to the photonic devices of an optical sub-assembly. The method comprises arranging a chip-sub-assembly having electrical connections on a connector sleeve configured to receive a connector plug and configuring a connector plug to include optical fibers and an optical sub-assembly having photonic devices with electrical connectors wherein the photonic devices are optically coupled to the photonic devices. The method including the further steps of engaging the connector plug with the connector sleeve so that the electrical connectors wherein the photonic devices are in electrical contact with the electrical connections of the chip-sub-assembly.